Rinse the cranberries under running water. Remove any bruised or mushy fruit and discard. Set aside.
Combine granulated sugar and water in a small heavy saucepan over medium-high heat, stirring until the sugar dissolves. Bring to a simmer; remove from heat.
Combine the sugar syrup and cranberries in a small bowl. Cover and chill for 4 hours.
Drain the cranberries in a colander over a bowl, reserving liquid for another use, if desired. Place the superfine sugar in a shallow dish or rimmed plate. Add the cranberries, a few at a time, rolling to coat.
Spread the sugared cranberries in a single layer on a baking sheet; let stand at room temperature 1 hour or until dry.